This invention relates to a cutting apparatus for sheet-like materials such as rubber sheets, and more particularly to a sheet-like material cutting apparatus having means for detecting configurations of cut ends of the rubber sheets having cords embedded therein in parallel with each other when the sheets are cut.
There have been various kinds of apparatus for cutting rubber sheet materials such as carcass materials, steel breakers and the like. For example, a cutting apparatus has been proposed which is able to cut steel breakers in bias directions of steel cords embedded therein without cutting the steel cords or without exposing the cords at cut ends (Japanese Utility Model Application Publication No. 62-13,779).
With the apparatus of the prior art, a disk-like cutter having a V-shaped section is driven in the bias directions on the rubber sheet to cut it diagonally. The cutter is movable in the bias directions and also directions perpendicular thereto.
Therefore, the V-shaped cutting blade of the cutter moves so as to avoid the embedded steel cords so that any steel cords are not cut. Moreover, the V-shaped cutting blade presses and deforms the sheet material and cut the material so as to cover the cut end of the material by its outer coating. Accordingly, steel cords are not exposed at the atmosphere.
Since the steel cords are not exposed at the cut ends, where both the ends abut against each other and are jointed, a complete joint of the ends can be established and any peeling of the jointed portions is prevented.
In general, rubber sheet materials are stocked in rolled condition in a supply process and a required amount of the material is paid out of the roll and cut in use.
Therefore, cords embedded in the rubber sheet materials would lose their straightness and their bias angles would be changed by bad stocked conditions and mishandling in paying off.
In case of the above apparatus (The Japanese Utility Model Application Publication No. 62-13,779), even if cords in rubber sheet materials are curved or bias angles are changed, the cutter is moved along the cords without cutting the cords because the cutter is movable in a direction perpendicular to its traveling direction.
However, it is impossible to avoid problems when cutting configurations of the rubber sheet materials are curved or bias angles are different from predetermined bias angles after being cut.
Therefore, if the such a cut rubber sheet material is supplied to a next process, various troubles would occur.
In more detail, if the rubber sheet material is wound about a drum to joint its abutting cut ends of the material in the next process, the cut ends are often overlap or form clearances therebetween to lower the quality of the tire product.
In a process of jointing cut ends of a rubber sheet material in overlapping, moreover, such a rubber sheet material having curved cut ends and different bias angles also lowers the quality of the tire product for the above reason such as existence of non-uniform overlapped ends and, in the worst case, partial clearances.